Presentation on theme: "The Integumentary System"— Presentation transcript:
1 The Integumentary System The skin, hair, & nails…The “underappreciated” system
2 Objectives:List the components of the integumentary system & describe their physical relationship to each other & to the subcutaneous layer.Specify the general functions of the integumentary systemDescribe the main structural features of the epidermis, and explain their functional significanceExplain what accounts for individual and racial differences in skin, such as skin colorDiscuss the effects of ultraviolet radiation on the skin and the role played by melanocytes.Describe the structure and functions of the dermisDescribe the structure and functions of the subcutaneous layerDiscuss the various kinds of glands in the skin and the secretions of those glandsExplain how the sweat glands of the integumentary system play a major role in regulating body temperature.Explain how the skin responds to injury and repairs itselfLearn selected clinical terminologyblahblahabl
3 Integumentary Overview The integument includes the cutaneous layer or skin which includes the epidermis & dermis.The accessory structures include hair, nails, and multicellular exocrine glands.Deep to the dermis, the loose connective tissue of the subcutaneous layer, or hypodermis.
4 Functions of the Integument ProtectionExcretionTemperature maintenanceNutrient StorageVitamin D3 synthesisSensory Detection
5 The EpidermisThin skin formed by 4 layers of keratinocytes covers most of the bodyThick skin covers palms of hands & soles of feet.Provides mechanical protection, prevents fluid loss, keeps out bugs
9 Stratum germinativum Innermost layer Forms epidermal ridges - extend into the dermis, increasing area of contactDermal papilla extend between ridgesRidges = fingerprints; increase surface area of skin and increase friction.Unique to individuals!!
10 Germinative cells dominate layer These cells undergo mitosis (stem cells)Merkel cells (touch receptors) found on skin surfaces which lack hair.Melanocytes present in layer. These cells contribute to skin color.
11 Stratum Spinosum “spiny layer” Consists of 8-10 layers of cells Spiny appearance due to tissue prepLangerhans cells present - these cells participate in the immune response.They stimulate defense against 1) microorganisms & 2) superficial skin cancers
12 Stratum Granulosum “Grainy Layer” 3-5 layers of karatinocytes Cells have stopped dividing by nowMake lots of keratin. - protein, waterproof
13 Stratum Lucidum Found only in “thick skin” Palms of hands & Soles of feetClear layerCells are flattened, densely packed, and filled with keratin.
14 Stratum Corneum Top layer 15-30 layers of keratinized cells Cells shed from this layer in large groups15-30 days for a cell to move from s.germinativum to s. corneum.Cells remain in S. corneum approx. 2 weeks before shed or washed away.Water resistant layer, not waterproof
15 Skin colorInteraction between epidermal pigmentation and dermal circulationCarotene & melanin important pigmentsCarotene = orange-yellow pigmentCarotene converted to Vitamin AMelanin = brown, yellow-brown, or black pigmentation made by melanocytes
16 Melanocytes… Located in the stratum germinitivum Regardless of ethnic variation, the ratio of melanocytes to germinative cells ranges between 1:4 and 1:20, depending on region of the body.Variation in skin color due to synthetic activity of the melanocytes, not numberMelanin protects against UV damage.